I've been seeing a fair number of examples of people having success with high volume, very easy running. I've read about the Japanese Method (massive volume at ridiculously easy efforts, then hitting workouts super hard). I've read about Yuki Kawauchi's training (singles, high volume, mostly very easy with one track session + one tempo per week). I'm not looking for an argument on if this is the best way to train - rather looking to see some more anecdotes and examples of people having success with it, particularly if I have to do singles most of the time (they can be longer singles of 80-120min, but how much is too much to do daily?). I understand I could do higher quality and run less, but when I try a more conventional program I get injured.
Background - I'm a 22yo guy, at ~17 flat for 5k, 1:20 HM, absolutely no speed and the track beats me up. Used to be low volume high quality (25-30mpw with 2 hard workouts + a hard long run). Never ran slower than 7-7:20/mi. Now I run 50-55mpw of mostly easy stuff (usually 8:20-8:50/mi) and am going to be slowing it down and bumping my mileage higher (hopefully 70-80mpw).